Guerbet alcohols have been known for over 100 years now. Marcel Guerbet pioneered the basic chemistry in the 1890s. It has allowed for the synthesis of a regiospecific beta branched hydrophobe which introduces high purity branching into the molecule. Guerbet Alcohols, the oldest and best-understood material in the class of compounds, have been known since the 1890's when Marcel Guerbet first synthesized these materials.
The reaction sequence, which bears his name, is related to the Aldol Reaction and occurs at high temperatures under catalytic conditions.

The product is an alcohol with twice the molecular weight of the reactant alcohol minus a mole of water. The reaction proceeds by a number of sequential steps. These steps are (a) oxidation of alcohol to aldehyde, (b) Aldol condensation after proton extraction, (c) dehydration of the Aldol product, and (d) hydrogenation of the allylic aldehyde. The reaction takes place without catalyst, but it is strongly catalyzed by addition of hydrogen transfer catalysts. At low temperatures 130–140° C. the rate-limiting step is the oxidation process (i.e. formation of the aldehyde). At somewhat higher temperatures 160–180° C. the rate-limiting step is the Aldol Condensation. At even higher temperatures other degradative reactions occur and can become dominant.
Many catalysts have been described in the literature as effective for the preparation of Guerbet Alcohols. These include, nickel, lead salts (U.S. Pat. No. 3,119,880), Oxides of copper, lead, zinc, chromium, molybdenum, tungsten, and manganese (U.S. Pat. No. 3,558,716). Later US patents (U.S. Pat. No. 3,979,466) include palladium compounds and silver compounds (U.S. Pat. No. 3,864,407). There are advantages and disadvantages for each type.
The Cannizzaro Reaction is a major side reaction and is described as the disproportionation of two molecules of an aldehyde brought about by the action of sodium or potassium hydroxide to yield the corresponding alcohol and acid. On a practical level, it results in a product that is both difficult to purify and has undesired impurities present. As a result, the ability to capitalize upon the Guerbet reaction and develop useful, cost-effective derivatives has eluded scientists for many years.
A major problem with the currently used Guerbet products is the fact that they are sold as very high purity products, requiring elaborate clean up processes and post treatments to make products that find applications mostly in cosmetic products. Guerbet alcohols undergo a series of post reaction steps that (a) remove unreacted alcohol (vacuum stripping), (b) remove unsaturation (hydrogenation), (c) remove Cannizzaro soap (filtration) and (d) remove color/odor bodies. These operations add to the cost of the product and make their utility impractical. All inventions covering Guerbet alcohols and their derivatives were made using highly purified materials which not only limited the usefulness due to costs, but also, as will become apparent by this disclosure, resulted in mono-modal surfactants that lack the highly efficient emulsification properties that result when using lower purity products. By lower purity products is meant those products in which unreacted raw material alcohol is left in the mixture and subsequently co-alkoxylated then sulfated to give bi-modal surfactants having unique emulsification properties.
Most commonly, alcohols of natural origin, which are straight chain, even-carbon, primary alcohols are used for the production of Guerbet alcohols. Guerbet alcohols are beta branched primary alcohols. Oxo alcohols can also be used, but the reaction rate and conversions are reduced. Blends of primary alcohols could, of course, be used as starting materials to achieve desired economics or end-use functionality.
U.S. Pat. No. 6,610,751 issued Aug. 26, 2003 to O'Lenick et al discloses the starting alkoxylates used to make the compounds of the present invention and are incorporated herein by reference.
We have surprisingly found that by sulfation of the low purity guerbet bi-modal alkoxylate, a very potent emulsifier results. Said surfactant is an outstanding emulsifier for hydrocarbons, chlorinated hydrocarbons and other non-polar liquids. These emulsifiers are outstanding when used with crude petroleum and other non-polar compounds, and consequently are useful in enhanced oil recovery and remediation of contaminated soil. Other end uses that require such potent emulsification properties include emulsification and wetting of agricultural active ingredients as well as emulsification of monomers in polymerization processes.